It is necessary in many copying and sorting machines, such as described in commonly owned allowed patent application Ser. No. 533,578 filed Sept. 19, 1983 now U.S. Pat. No. 4,497,478, of R. Reschenhofer et al, to provide a mechanism for squaring up, that is aligning one atop the other, the sheets that are fed in either one at a time or in groups. When the sheets are to be stapled or bound by an automatic device, it is absolutely essential that they be in proper alignment.
A standard such device is German Pat. No. 649,028. It has a support plate on whose surface the sheets are deposited. Several pins are fixed along one edge of the plate, and several movable pins carried on arms or rods underneath the plate project up through slots in this plate. A mechanism is provided to move these latter pins toward the stationary ones to push the sheets thereagainst and thereby align and square them up.
The main problem with such a device is that the stroke of the movable pins must be very carefully adjusted. If it is too short the sheets will not be properly aligned; if it is too long the edges of the sheets will be crumpled. In addition if a sheet gets slightly jammed, it will be damaged, necessitating manual correction.